Biology 122 Spring, 2008

Laboratory 12

Pericardium, Heart and Superior mediastinum

OBJECTIVES

At the end of this laboratory you should:

1. Understand the mediastinum, its two major divisions, and the subdivisions of the inferior mediastinum.

2. Know the structure of the pericardium and the spaces within the pericardial cavity (oblique and transverse pericardial sinuses).

3. Know the innervation of the heart via the cardiac plexus with its sympathetic, parasympathetic and afferent components. The concept of referred pain should be studied, with special reference to cardiac pain.

4. Understand the position of the great vessels, heart and cardiac valves relative to the anterior chest wall. You should be able to orient an isolated heart in its normal position in the body.

5. Know the blood supply of the heart (left coronary artery with anterior interventricular, circumflex and marginal (ventricular) branches; right coronary with branch to SA node, ventricular (acute marginal) and posterior interventricular arteries). The distribution of these vessels to specific parts of the heart and clinically significant variations should be appreciated.

6. Know the three classes of veins that drain the heart.

7. Understand the organization, structure, and functional significance of the internal features of the heart.

a. Right atrium - sulcus terminalis; sinus venarum cavarum, crista terminalis, musculi pectinati; right auricle; interatrial septum, fossa ovalis, limbus fossa ovalis, ostium of the coronary sinus, valve of the coronary sinus, valve of the inferior vena cava, right atrioventricular ostium and its tricuspid valve.

b. Right ventricle - trabeculae carneae, papillary muscles, chordae tendineae; anterior, septal and posterior cusps (leaflets) of the right AV valve, septomarginal trabecula (moderator band), supraventricular crest, conus arteriosus (infundibulum), pulmonary valve with its semilunar cusps (left, right and anterior), and for each cusp the nodule, lunule, and sinus.

c. Left atrium - valve of the foramen ovale, superior and inferior pulmonary veins on each side, ostium of the left AV (mitral) valve.

d. Left ventricle - trabeculae carneae, papillary muscles, chordae tendineae, the cusps (leaflets) of the right AV valve, semilunar cusps of the aortic valve (left, right and posterior), and aortic sinus openings for the coronary arteries.

8. Gain a basic understanding of the nodes (SA and AV) and special conduction system of the heart.

PRELABORATORY PREPARATION

1. Read the introductory section in your textbook on the cardiovascular system (pp. 39-44).

2. Read the chapter in your text covering the mediastinum and its divisions, the pericardium, heart and great vessels (pp. 135-169).

3. Attention should be given to sections in your textbook covering:

1. the mediastinum and its subdivisions.

2. the innervation of the heart (p. 163-135).

3. referred pain, especially relative to heart disease and the diaphragm (pp. 166-167).

4. Read the introductory material in your textbook on the autonomic nervous system (pp. 58-67).